Jacket for safety-fuses.



C. N. SACHS. JACKET FOR SAFETY FUSES. APPLICATION FILED MAR,11,1904. RENEWED DEC. 8. 1911.

1,01 6,443. Patented Feb. 6, 1912.

. /5 Wit messes U By My Application filed March 11, 1904, Serial No. 197,654. Renewed December 8, 1911.

UN TED STATES. PATENT OFFICE.

CAROLINE N. SACHS, OF HARTFORD, CONNECTICUT, ASSIGNOR TO THE SACHS COMPANY, OF HARTFORD, CONNECTICUT,-A CORPORATION OF CONNECTICUT.

JACKET FOR SAFETY-FUSES.

Specification of Letters Patent.

Patented Feb. 6, 1912.

Serial No. 664,652.

To all whom, it may concern:

Be it known that I, CAROLINE N. SACHS, a citizen of the United States, and resident of Hartford, in the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in Jackets for Safety-Fuses, of which the following is a full, clear, and exact specification.

This invention comprises a new and improved safety fuse jacket or casing for electrical connections, and a process'of making the jacket; These fuses comprise wires or strips of suitable metal, which' is fusible by a current temperature too low to affect the conductors or other devices which the safety fuse is designed to protect. 'In fuses as heretofore made the fusible strip is commonly inclosed in a tube or similar receptacle containing loose powdered or granular insulating material which surrounds the fusible strip and its connected terminals. Upon the rupture of the strip by an excessive current, the heat of "theexpanding gases arising therefrom is absorbed and the arc disrupted by the surrounding filling material. is this filling material is used in a loose condition, and hence is not self-sustaining, it was necessary to inclose it in a tube or envelop sufliciently strong and heavy to confine the powdered material afely andfirmly in conformity with and around the strip, and to withstand the strains incident to the rupture of the strip and the packing, handling and using of the .fuse.

In the present invention the fusible strip and its terminals are inclosed in an integral cellular or multi-chambered structure which is in itself sufiiciently strong so that it may be used without any tube or casing. The cellular interstices, cavities or chambers afford ample provision for the safe dispersion and absorption of the heat. and gases produced by the rupturing of the fuse strip. In the drawings, Figure 1 is a plan vie-w in section taken through the longitudinal center of the fuse; and Fig. 2 is a side View showing the exterior appearance of my pre ferred form of this improved fuse, mounted in a well-known way. Fig. 3 is an end view in transverse section, showing a modified construction of the fuse.

The fusible wire or strip 5 of a suitable fusible metal, which may be of any desired section, is connected between the terminal strips (5 of copper, or other metal which is fusible only at a higher temperature than the'fuse 5. These terminals are continued to and joined in the electric circuit in any well-known or convenient way, as for example, by the ferrules 8 and 9. 'A- con- 'venient wayof mounting these fuses is to insert the terminals between spring clips 10, attached to a base 11 of insulating material, the clips being provided with binding posts, to which are attached the terminal wires 12 of the circuit, which is to be carried through the safety fuse.

The fuse-inclosingjacket 15 is constructed of a length and thickness suitably proportioned to the capacity of the fuse, and to the strains incident to its handling and use. It comprises an integral multi-chambered structure containing numerous interior cellular cavities, the interior structure shown in cross section in Fig. 1 being comparable to that of, a sponge or pumice or well-baked bread, the'interstices or cells of which'become from the burning out of the fuse, thus preventing the'formation of an arc by permitting those gases to be dispersedand the heat absorbed and generally rendered harmless. The metallic particles of the disrupted fuse are also dispersed through the ramifications of the cells, and are too widely dispersed and disconnected'to permit the reformation of a conducting chain between the terminals. This self-supporting cellular jacket 15 may1 be.v made in variousways and of different.

.kinds of. material suited to this purpose.

According to my present information I preferably employ plaster of Paris, chalk and asbestos fiber, with which the necessary amount of gas generating material such as sesquicarbonate of ammonia, bicarbonate of soda, tartaric acid or similar material has been incorporated, so that when these combined elements are mixed or otherwise formed into a plastic mass and molded around the wire, the gas developed during, the drying and hardening of the entire mass, which may be either with or without the application of heat, will result in the formation of the=cells in the completed jacket. Other cellular structures, such for example permeated with the gases resulting as may be produced by felting or similar processes, may also be employed for the jacket.

Although these cellular jackets may be made sufliciently strong for all practical purposes, without any reinforcing tube or casing, it may be considered preferable for general commercial purposes to roll or wrap them in a'paper envelop which may also serve as a label orwrapper, which, however, may be of comparatively thin paper, suitably-printed or embellished; and perhaps also varnished to'improve the external appearance of the fuse as a commercial article,

and protect it against outside moisture.

The cellular jacket may also be formed by placing the fusible strip and its enveloping material in a tube while the enveloping material is in a plastic condition, and allowing the jacket to harden, and bind the parts together. Or the jacket may be formed around the wire. and then both be placed in an exterior shell or tube to which the-external terminals are attached. Instead. of forming the cellular mass on and around the fuse strip, the jacket may first be formed, leaving one or more openings through it into which the wire may subsequently be, passed.

- In any case either one or'a plurality of-fusible ,st rips ma be employed to connect the terminals. Th dispensed with and the terminal connections be made in any well-known Way that may be best adapted to the devices or the environment in which the fuses are to be employed.

In the modification shown in 'Fig. .3 the core of the fuse is shown to be provided with a, tube or envelop 18, which may extend the entire length of the jacket 15, or extend only between the inner ends of the ferrules 8 and 9. The tube or envelop 18 may be of any suitable materials, such for example as those now used for this purpose. The porous or cellular jacket 15 may be made of any suitable insulating refractory material or combination of materials other than those hereinbefore named; and they e metallic ferrules may be' may be reduced to a plastic condition by mixing with water or any other liquid suited to the materials employed.

In various other ways which will suggest themselves to those familiar with this art, the invention herein shown may be modified to suit different environments and various conditions of service.

I claim as my invention 1. An integral fuse jacket provided with a multiplicity'of gas dispersing cavities.

2. A fuse casing comprising a tube having 5. In a safety fuse, the combination with the fuse strip, of an integral jacket of cellular gas dispersing structure.

6. In a safety fuse, the combination w1th the fuse strip, of an integral gas dispersing cellular jacket surrounding and inclosing the fuse strip and its connected terminals.

7. In a safety fuse, the combination with the ,fuse str'p, of a jacket surrounding the strip, consi's ing of an integralgas dispersing cellular structure of insulatmg material.

8. In a safety fuse, the combination with the fuse strip, of an integral jacket of gas dispersing cellular structure, surrounded by an external inclosing envelop.

In testimony whereof I have signed my name to this specification in the presence of two subscribing wltnesses.

CAROLINE N. SACHS.

Witnesses:

WM. H. HONISS, 4 Las. IV. GREEN.

Copies of this patent may be obtained 'for five cents each, by addressing the Commissioner of Yatents,

Washington, D. 0. 

